Supplementary order, retroactive effect.

    (a) If any commission has made its final order for 1933 prior to the effective date of this act such commission is hereby empowered to hold necessary additional meetings, afford necessary additional hearings and enter a supplementary order making findings and authorizing the levy of an additional tax rate in harmony with the provisions of this act. Such supplementary order shall be in addition to and shall in no way invalidate, limit, or otherwise effect the final order previously entered.

    (b) If any commission has made its final order of 1933 prior to the effective date of this act and such final order has authorized the levy of an additional tax rate for a school district upon property lying within the boundaries of a municipal corporation, or has authorized the levy of a greater tax rate within the boundaries of the municipal corporation, than outside thereof, such order is hereby validated and rendered as effective as though made subsequent to the effective date of this act, and such order shall authorize the levy of such additional tax rate of any part thereof: Provided, however, That the commission may, if such previously made order is not in harmony with this act, hold necessary additional meetings, afford necessary additional hearings and enter an order amending such previous order to cause it to conform with this act. Such amended order shall stand as the final order of the commission for 1933 and shall be effective as such.